1. Field of the Invention
The present invention relates to an image output apparatus having a document reading section and an image output section, such as, a digital copying machine.
2. Description of Related Art
A digital copying machine or a so-called composite machine (an image forming apparatus having both a facsimile function and a copying function) comprises a document reading section for optically reading a document, an image memory for storing image data representing an image on the document read by the document reading section, and an image forming section for reading out the image data from the image memory to form a reproduced image of the document.
The document reading section comprises one document holding section for putting a document to be read, one document discharging section for receiving the document which has been read, a document conveying mechanism for conveying the document along a path leading to the document discharging section through a document reading position from the document holding section, and a reading mechanism for reading an image on the document at the position to convert the document image into image data.
The document reading section takes out and conveys a group of sheet documents composing one document one at a time and successively reads an image on each of the sheet documents.
If another document is added and is put on the document holding section during document reading processing, it is possible to continuously run, subsequently to one job (in this case, the document composed of the group of sheet documents), another job. In this case, however, the sheet documents or output images are inevitably mixed up.
So long as a plurality of jobs must be distinguished, therefore, the plurality of jobs cannot be collectively reserved. Accordingly, it is necessary to perform a document setting operation for each of the jobs.
In order to make a copy of the job, which has been copied once, again at another opportunity, all the sheet documents composing the job must be subjected to reading processing again. Consequently, the image data has not been made effective use of, although it is stored in the image memory.